With the help of recently developed eye-tracking technology, the researchers investigated the effects of eye contact in situations involving persuasion in a series of experiments.

They found that on various controversial issues, the more participants watched a speaker's eyes, the less persuaded they were by the argument of the person speaking.

Spending more time looking at someone's eyes as they spoke was only associated with greater receptiveness among participants who already agreed with the speaker on that issue, according to the researchers.

"Whether you're a politician or a parent, it might be helpful to remember that trying to maintain eye contact may backfire if you're trying to convince someone who has a different set of beliefs than you," said co-author Julia Minson of Harvard' s Kennedy School of Government.